1. Field of the Invention
The present invention relates to a method and apparatus for controlling the pumping rate of internal combustion engine driven pumps, and more particularly, but not by way of limitation, to a method and apparatus for controlling the liquid pumping rate of an internal combustion engine driven pump taking suction from a surge tank whereby a substantially constant level of liquid is maintained therein.
2. Description of the Prior Art
In many industrial applications, and particularly in oil fields, internal combustion engine driven pumps are utilized for pumping liquid from one or more surge tanks to points of use. For example, in water flood and other secondary oil and gas recovery operations, water or other similar liquid is pumped into a subterranean formation by way of one or more injection wells to drive the desired fluids contained in the formation to production wells. In water flood operations, water produced by way of the production wells is separated from the recovered fluids and recycled to one or more surge tanks from where the water is again pumped into the injection wells. In remote locations where natural gas is readily available or more economical than electricity, internal combustion engines are utilized to drive the pump or pumps taking suction from the surge tanks. Since the rate of liquid pumped must vary with the supply of liquid available, it is necessary that such rate be controlled so that a substantially constant level of liquid is maintained in the surge tank or tanks.
While a great variety of level control and other control apparatus has been developed and used, most of such control apparatus heretofore utilized for controlling the liquid pumping rate of an internal combustion engine driven pump has been elaborate, expensive and subject to upsets and/or failures.
By the present invention, a method of controlling the liquid pumping rate of an internal combustion engine driven pump taking suction from a surge tank and apparatus for carrying out the method are provided which are simple, economical and extremely reliable.